Airplane light



Dec. 2, 1941. 1 ADLER, JR y2,265,095

AIRPLANE LIGHT Find Aug. 2s. 1941 I n 'venture Charles 0165292", '-71.1'

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Patented Dec. 2, 1941 l UNITED sTA'LEs. 'PATENT OFFICE i 2.265.095 y Y Q CMJIL'M- Application Aunt ze, 1941, serialize. 408,393

` (cl. 1v1-337) f- 4Claims.

This invention relates to running or position lights and is particularly useful in connection with airplanes where it is adapted to be attached,

for example, to the rudder as a tail light.

The object of the invention is Vto 'provide a light of this character inwhich there is continuously projected alternately from a single visible area, namely, a cover glass, rapidly consecutive contrasting colored llight indications of sumantially equal intensity and distribution with a short dark interval between each light indication Figure 3 is a horizontal sectional plan viewof a modification:

Figure 4 is a horizontal sectional plan view of a further modiiication: and Y Figure -5 is a diagrammatic view of one form of electric system including a flasher relay for alternately energizing the light sources. y

Referring to Figure 1, the numeral I0 indicates a housing or casing which is made of metal or plastic and which is substantially tubular in cross section. At one end of the housing there is dewhereby a highly distinctive and arrestive form of indication is produced having the particular advantage that there is no increase iny drag or appreciable adding of weight.

It is generally admitted that the 'conventional steady white or clear tail light lacks distinction and is readily confused with lights on the ground.

, A iiashing white light, while an improvement,

still as actual tests show, may be confused with lights of moving vehicles on the ground such as automobiles passing lunder trees or moving past telegraph poles. The lamp of the .present inventionV flashes alternately white or-clear and another color suchas red or green with a predetermined dark interval between each ilash and in` h 4paths which rays from said other source follow when the latter is energized. The entire unit is streamlined in accordance with aerodynamic principles and both colors are projected from a single opening or cover glass through angles ranging from 140 to 180 horizontally as well as vertically, the light sources being disposed in longitudinal alignment with each other substantially on the axes of the members of the optical system. The light unit has no moving parts and a flasher relay is preferably employed which is located remote from the light inside the'airplane where it will not be subject to freezing.

In the accompanying drawing, I have illustrated several embodiments of the invention and the invention is subject to modification within the scope of the appended claims.

Referring to the drawing:

Figure 1 is a horizontal sectional plan. view;

Figure 2 .is a vertical sectional plan view:

tachably secured a suitable cover glass II which forms a single visible signal area and at the opposite end of the casing, there is a detachable opaque end I2. The cover glass II, body I0 and end I2 are streamlined in accordance with aerodynamic principles.

In a preferred form of the invention, two light sources in the form of incandescent electric lamps I3 and I4 of suitable candlepower are disposed in longitudinal alignment with each other and with the cover glass II in the casing i0, the lamps y being heldiirmly in position in the usual bayonet sockets l5.

Disposed in advance of the light source Il is a convex lens I6 and preferably a doublet lens arrangement consisting of the lens I6, and a convex lens Il spaced as shown inFigure l is -provided. While I have illustrated the convex lens I6 as smaller in diameter than the lens Il, both lenses may be of the same size. It has been found, however, to be good practice, to have the lens I6 ofsmaller diameter and also to have the lens I6 with its prismaticsteps-I8 on the 'convex side and the lens Il with its prismatic steps i9 on the concave side. The filaments of the lamps are longitudinally aligned substantially on the axes of the lens I6 or lenses I6-i1, the cover glass II and a reflector where the latter is employed, as will be later described.

The important consideration as regards the optical system is so to focus the light sources and lens or lenses that rays of light from the source I4 are retracted by the lens or lenses so that the rays converge at the filament of the light source I3 as shown at 20 and pass through this other source as colored rays which are coincident with the paths of the rays from the light source I3 when the latter is selectively energized.

This constructionis advantageous because it permits the light sources to be disposed in longitudinal alignment with each other and on the axes of the lens or lenses and the cover glass and f reector when the latter is used, so that a small compact structure is provided which does not create drag, and assures that the intensity and distribution of both the white or clear light and the red or green light will be substantially the same when alternately presented at the signal area II.4

The lamp I4 may be suitably colored or one or the other of the lenses I6 or Il may be colored. The cover glass I I, of course, is clear.

YWhen the lamp I4 is illuminated, a red beam is visible through the cover glass and when the lamp I4 is de-energized there is presented a dark interval of predetermined length by the cover glass whereupon the lamp I3 is energized, and a white or clear beam is visible. When the lamp I3 is de-energized, the sequence described of dark interval followed by the red indication continues. 'I'he cover glass is of any suitable construction which will give a Wide light distribution, e.g., from 140 to 180 and in the present instance, I have shown it as having a prismatic structure at 2|.

In some cases, although it is not usually neces.- sary, a suitable reflector 22 may be employed to i utilize the rays which may be directed rearwardly rfrom the lens as shown in Figures l and 2.

Referring to Figure 3, I have shown amodifica'- tion in which a spherical reflector` 23 is employed.

With this construction, the rays from-.the light source I4, directed upon the reflector 23, are reflected thereby asv shown to also converge upon the filament of the lamp I3 in the manner previously described. i The lens or lenses I6 or I6-I1 are omitted in this construction and instead thereof I will either use a colored lamp I4 or an ordinary lamp with a suitably colored roundel 24. In this construction, the filaments are longitudinally aligned on the axes of the reflector and cover glass and the" roundel where used and a light weight structure in which drag -is substantially eliminated, is produced;y While I have illustrated the casing and housing with two independent light sources, e. g. incandescent lamps, it is to be understood that the housing itself may be a sealed bulb or casing in which are disposed two filaments and the preferred and modied constructions may be incorporated in the same or preferably a reectihg surface is employed and a red transparent screen is interposed between the filaments after the manner of Figure 3. Referring to Figure 4, I have illustrated a construction of `this character in which the streamlined body 26 is of suitable material such' as glass or plastic and formed into j nan integral sealed bulb which may be made cylindrical and which is either gas filled or evacuated. At one end and on the exterior or interior thereof, the blb is suitably silvered to provide a mirror surface 2'I in the form of a substantially spherical structure. At its opposite or light visible end 28, the glass has a prismatic contour.

Preferably the end 28 is attached to the mirrored portion of the body by fusing to make a sealed container inthe well known manner as shown at 2li. Within the bulb are supported a and in paths coincident with the rays-from the source 29. The structure eliminates any increase in drag and the weight of the light is not appreciable. I

In Figure 5, I have illustrated a conventional flasher relay circuit in which the relay R may be disposed remote from the light. This circuit is of any suitable character for continuously op erating to first energize and de-energize one lamp, break contact for a predetermined brief interval to render the cover glass dark and then energize and de-energize the other lamp so as to give a distinctive and arresting flashing signal.

-In this connection, a conventional motor driven asherY such as is now commercially available or an air actuated flasher relay may be employed to give this flasher indication as described in my co-pending application Serial No. 406,037, filed August8, 1941.

Referring to Figure 2, I have illustrated in .Figures 1, 3 and 4 diagrammatically the path of rays from the vlamp I4 and the filament 30 and in all cases rthe filaments or light' sources and the members of the optical system are so positioned and focused that these rays converge at the filament of the lamp I3 or the filament 29, as shown at 20, ascolored rays and pass through these filaments to the cover glass II from which they are projected outwardly through angles of sub` stantially to 180 as shown at 35. The paths of these colored rays between the'fllament of the lamp I3 or the filament 29 and the cover glass are coincident with the paths which rays given c from said filaments follow when the same are energized, so that the alternate light indications from the cover glass II are of `substantially equal intensity andl distribution.

The numerals 36 and 3l indicate narrow gauge wire fastening means for detachably connecting the cover glasseand opaque end of the casing to the body thereof. Other suitable connecting or holding means may, of course, be used.

It has been found that a flashing indication of the character described, namely, one which flashes red or some other color for a predetermined interval, then remains dark for a predetermined interval, then flashes white or another color for a predetermined interval and then remains dark for a predetermined interval, and continuously repeats the sequence described, pro vides an arrestive signalwhich solves the problem of running lights for airplanes, as has been demonstrated byv actual tests. The relay employed, as stated, may be of any suitable conventional character, provided it is regulable to give predetermined periods of energization to the lamps with a predetermined period of de-energizatlon between each flash of any filament. Preferably,

' the de-energization interval is less than the energizationperiod of any filament, but, of course, it may be equal to and in some cases greater than such periods. The discovery which I have made is that the objectionable obscurity characteristic I of airplane lights is remedied and a clear, sharp arrestive signal given by a ashing indication using contrasting colors presented from a single cover glass and in which a dark interval is presented between each flash.

'Ihe term light projecting devices as used in the appended claims, is intendedto cover any combination of light source and color producing means so as to comprehend the clear lamps I3 and the construction for producing a contrasting color wherein the lamp I4 either has its bulb surface' colored or is associated with any suitable type of color producing means such as a colored lens, a colored roundel, or a colored screen. In other words, the expression light projecting devices is intended to cover the means by which beams diilerently colored from and contrasting from each other are produced.

This application includes related subject-matter of my co-pending applications Serial Nos. 405,867 and 409,876.

Iclaim: y 1. An airplane position signal comprising a plurality of light 'projecting devices, each pro-v 2. An airplane position signal comprising a plurality of light projecting devices, each producing a beam differently colored from and contrasting from each other, cover glass means' for distributing the light from said de'vces through an angle of at least substantially 140 horizontally and vertically, and means for energizing and deenergizing each of said light projecting devices in sequence and for maintaining all of the same deenergized for a predetermined time period afterthe illumination of one of said light projecting devices whereby the signal continuously presents alternately contrasting illuminated colored indications and a dark indication after an illuminated indication.

3. An airplane' position signal comprising a single casing having therein a plurality of light projecting devices, each producing a beam differently colored from and contrasting from each other, means for distributing the light from said devices through an angle of at least substantially horizontally and vertically, and means for energizing and deenergizing each of said light projecting devices in sequence and for maintaining all of the same deenergized for a predetermined time period after the illumination of one of said light projecting devices whereby the signal continuously presents alternately contrasting illuminated colored indications and a dark indication after an illuminated indication.

-v 4. An airplane position ysignal comprising a single casing having therein a plurality of light projectingdevices, each producing a beam differently colored from and contrasting from each other, cover glass means for distributing the light from said devices through an angle of at least substantially 140 horizontally and vertically, and means for energizing and deenergizing each of said light projecting devices in sequence and for maintaining all or the same deenergized for a predetermined time period after the illumination of one of saidlight projecting devices whereby the signal continuously presents alternately contrasting illuminated colored indications and a dark indication after an illuminated indication.

CHARLES ADL'ER, Jn. 

